Proteins are macronutrients that are essential for building and repairing tissues in the body, including muscle, bone, skin, and organs. They are made up of amino acids, which are the building blocks of protein.
There are many different types of proteins found in foods, including:
- Animal proteins: These include proteins found in meat, poultry, fish, eggs, and dairy products.
- Plant proteins: These include proteins found in beans, legumes, nuts, seeds, and some grains.
When we consume proteins, they are broken down into individual amino acids during digestion. These amino acids are then absorbed into the bloodstream and used by the body for a variety of functions, including building and repairing tissues, producing enzymes and hormones, and supporting the immune system.
Unlike carbohydrates and fats, proteins are not a primary source of energy for the body. However, in times of low energy availability, such as during fasting or intense exercise, the body can break down proteins into glucose for fuel.
It’s important to consume a variety of protein sources as part of a healthy diet, including both animal and plant-based sources. This can help ensure adequate intake of all essential amino acids, which are amino acids that the body cannot produce on its own and must obtain from food. The recommended daily intake of protein varies depending on age, gender, and activity level, but generally ranges from 0.8 to 1.2 grams per kilogram of body weight per day but different diets accommodate different quantities of proteins.
Animal proteins
Animal proteins are proteins that are derived from animal sources, such as meat, poultry, fish, eggs, and dairy products. Animal proteins are considered “complete” proteins because they contain all of the essential amino acids that the body needs to build and repair tissues.
When we consume animal proteins, they are broken down into individual amino acids during digestion. These amino acids are then absorbed into the bloodstream and used by the body for a variety of functions, including building and repairing tissues, producing enzymes and hormones, and supporting the immune system.
There are many different types of animal proteins, each with its own unique nutrient profile and health benefits. For example:
- Lean meats: These include meats like chicken, turkey, and lean cuts of beef and pork. Lean meats are a good source of protein and other nutrients like iron, zinc, and vitamin B12.
- Fatty fish: These include fish like salmon, mackerel, and tuna, which are rich in heart-healthy omega-3 fatty acids and high-quality protein.
- Eggs: Eggs are a good source of protein, as well as vitamins and minerals like vitamin D, vitamin B12, and choline.
- Dairy products: Dairy products like milk, cheese, and yogurt are good sources of protein, calcium, and other essential nutrients.
Plant proteins
Plant proteins are proteins that are derived from plant-based sources, such as beans, lentils, nuts, seeds, and some grains. Plant proteins are considered “incomplete” proteins because they may lack one or more of the essential amino acids, but by combining different plant-based proteins, a person can consume all of the essential amino acids.
When we consume plant proteins, they are broken down into individual amino acids during digestion. These amino acids are then absorbed into the bloodstream and used by the body for a variety of functions, including building and repairing tissues, producing enzymes and hormones, and supporting the immune system.
There are many different types of plant proteins, each with its own unique nutrient profile and health benefits. For example:
- Legumes: Legumes, such as beans, lentils, and peas, are a good source of protein, fiber, iron, and other important nutrients.
- Nuts and seeds: Nuts and seeds are a good source of protein, healthy fats, fiber, and other important nutrients like vitamin E and magnesium.
- Whole grains: Whole grains like quinoa, brown rice, and barley are good sources of protein, fiber, and other important nutrients like iron and B vitamins.
- Soy: Soybeans and soy products like tofu and tempeh are good sources of high-quality protein, as well as other nutrients like calcium and iron.
Difference between animal and plant proteins
Animal proteins and plant-based proteins differ in their amino acid composition, digestibility, and nutrient content.
Animal proteins are considered “complete” proteins because they contain all of the essential amino acids that the body needs to build and repair tissues. Plant-based proteins, on the other hand, are considered “incomplete” proteins because they may lack one or more of the essential amino acids. However, by combining different plant-based proteins (such as beans and rice), a person can consume all of the essential amino acids.
In terms of digestibility, animal proteins are generally more easily digested and absorbed by the body compared to plant-based proteins. This is because animal proteins have a more similar amino acid profile to human proteins, and they also lack the fiber and other compounds found in plant-based foods that can interfere with protein digestion and absorption.
Animal proteins are also a good source of important nutrients like iron, zinc, vitamin B12, and vitamin D, which can be more difficult to obtain from plant-based sources. However, plant-based proteins are often rich in other important nutrients like fiber, antioxidants, and phytochemicals that can provide many health benefits.
What do our bodies use proteins for
When we consume proteins, our body breaks them down into individual amino acids, which are then used for a variety of functions throughout the body. Proteins are important for many bodily mechanisms, including:
- Building and repairing tissues: Proteins are the building blocks of tissues in the body, including muscle, bone, skin, and organs. They are essential for repairing damaged tissues and building new tissues.
- Enzyme and hormone production: Proteins are used to produce enzymes, which help to facilitate chemical reactions in the body, as well as hormones, which are chemical messengers that help to regulate various bodily functions.
- DNA repair: Proteins are important for repairing damaged DNA, which can help prevent mutations and reduce the risk of cancer.
- Immune function: Many proteins play a role in the immune system, helping to fight off infections and protect the body from harmful pathogens.
In terms of sources of protein, both plant-based and animal-based proteins can be important for meeting our protein needs and supporting these bodily mechanisms. Plant-based proteins can be especially important for individuals following a vegetarian or vegan diet, as they may need to rely on these sources to meet their protein needs.
It’s important to note that excessive protein consumption can also have negative effects on the body, including an increased risk of kidney damage, dehydration, and weight gain. Therefore, it’s important to consume proteins in moderation and focus on a balanced diet that includes a variety of protein sources.